What made Google Graveyard interesting was they were often successful or extremely popular products (and the list was well done).

Since then people have been posting Graveyards to show most businesses and products are never successful in the first place , but with a category filter to make it appear unique.

and then people get bored and stop updating them, soon we'll need a graveyard-graveyard to showcase all the failed graveyard projects.

Just thinking about how this could be useful and it could serve as an interesting counter example. So if you have an idea and you find it on this graveyard, it's probably something not to do or it might be worth thinking on a little longer before proceeding.